Same here! out of the blue my safari was taken over by same thing. At first safari window was resized to a square 1 inch by 1 inch and a msg appeared:
+
http://scanner2.malware_scan.com+
+NOTICE: if your computer has ben running slower than normal+
+it maybe infected with Viruses, Adware or Spyware+
+MalwareAlarm will perform a quick and cmpletely FREE scan of your system+
+for malicious programs.+
+Dawnload MalwareAlarm for FREE now!+
Than there was the option: cancel or OK
Well Macs don't get Viruses, right? so I confidently pressed 'cancel' and then boom my screen was taken over by this website.
I closed safari and reset it. Oh and by the way all this time 'Block pop-up windows' option was checked. Was it just a cookie that triggered all this or there's sth on my disk that I'm not aware of?
Oh and the thing is that for a week now or so (I think since last updates) - my Mac has been in fact sluggish...
Message was edited by: BigPole